Printing apparatus, control method for printing apparatus, and storage medium

ABSTRACT

A control method in a printing apparatus includes printing, by a printing unit, an adjustment image for adjusting a printing position on a sheet, conveying, by a conveying unit, the sheet on which the adjustment image is printed, reading, by a reading unit, an image to generate image data, the reading unit being executable to perform reading by a first reading method for reading an image of a sheet without conveying the sheet or a second reading method for reading the image of the sheet while conveying the sheet, and determining, based on that a type of the sheet on which the adjustment image is to be printed is a specific type, to read the adjustment image by the first reading method.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Divisional of U.S. application Ser. No.14/958,669, filed Dec. 3, 2015, which claims priority from JapanesePatent Application No. 2014-249412, filed Dec. 9, 2014, which are herebyincorporated by reference herein in their entireties.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a printing apparatus for printing animage on a sheet, a control method for the printing apparatus, and astorage medium.

Description of the Related Art

There is an image forming apparatus that reads a chart with a blackimage having a predetermined width being printed thereon in advance byusing an auto document feeder (ADF) to diagnose misregistration at aleading edge (see Japanese Patent Application Laid-Open No.2005-176045).

To read a document by using an ADF, for example, a document placed on adocument tray of the ADF is conveyed while an image of the document isread at a fixed position of an optical system. To read a document byusing a document positioning plate, for example, a document placed onthe platen glass (document positioning plate) is fixed while an opticalsystem is moved to read an image of the document.

For example, when images of a plurality of documents are read, it ismore desirable to use the ADF for reading them than to use the documentpositioning plate for reading them. The reason is that the plurality ofdocuments can be placed on the document tray of the ADF and thedocuments can be separated and conveyed one by one. This can reduce timetaken for a user repeatedly placing the documents.

An amount of shift of a printing position depends on physical propertiesof the sheet to print. Thus, for example, when a shift in the printingposition with respect to a sheet of high grammage is checked, a blackimage having a predetermined width needs to be printed on the sheet ofhigh grammage to output a chart. The chart of high grammage is moredesirably read by using the document positioning plate than by using theADF. The reason is that the chart of high grammage is difficult to bend,and when the chart is conveyed from the document tray of the ADF, thechart may fail to form a loop and can cause a jam on the way.

However, the image forming apparatus discussed in Japanese PatentApplication Laid-Open No. 2005-176045 scans a chart by using the ADF todiagnose misregistration at the leading edge. As a result, with atechnique discussed in Japanese Patent Application Laid-Open No.2005-176045, a jam can occur when a specific chart is scanned (forexample, chart of high grammage) by the ADF, and the amount of shift ofthe registration at the leading edge may fail to be obtained.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, a printing apparatusincludes, a printing unit configured to print an adjustment image foradjusting a printing position on a sheet, a conveying unit configured toconvey the sheet on which the adjustment image is printed, a readingunit configured to read an image to generate image data, the readingunit being executable to perform reading by a first reading method forreading an image of a sheet without conveying the sheet and a secondreading method for reading the image of the sheet while conveying thesheet, and a determining unit configured to determine, based on that atype of the sheet on which the adjustment image is printed is a specifictype, to read the adjustment image by the first reading method.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a configuration of a printingsystem according to an exemplary embodiment of the present invention.

FIG. 2 is an example of a sectional view illustrating a configuration ofan image forming apparatus according to an exemplary embodiment of thepresent invention.

FIGS. 3A and 3B are examples of a sectional view illustrating aconfiguration of a scanner unit according to an exemplary embodiment ofthe present invention.

FIG. 4 is an example of a table according to an exemplary embodiment ofthe present invention.

FIGS. 5A and 5B are diagrams illustrating configurations of screensaccording to an exemplary embodiment of the present invention.

FIG. 6 is an example of a schematic diagram illustrating an adjustmentchart according to an exemplary embodiment of the present invention.

FIG. 7 is an example of a table according to an exemplary embodiment ofthe present invention.

FIGS. 8A and 8B are diagrams illustrating detection processing accordingto an exemplary embodiment of the present invention.

FIG. 9 is a flowchart illustrating a control example according to afirst exemplary embodiment.

FIGS. 10A and 10B are diagrams illustrating configurations of screensaccording to the first exemplary embodiment.

FIG. 11 is a flowchart illustrating a control example according to thefirst exemplary embodiment.

FIG. 12 is a diagram illustrating a configuration of a screen accordingto the first exemplary embodiment.

FIGS. 13A and 13B are diagrams illustrating configurations of screensaccording to the first exemplary embodiment.

FIG. 14 is a diagram illustrating a configuration of a screen accordingto the first exemplary embodiment.

FIG. 15 is a flowchart illustrating a control example according to thefirst exemplary embodiment.

FIG. 16 is a diagram illustrating a configuration of a screen accordingto the first exemplary embodiment.

FIG. 17 is a diagram illustrating a configuration of a screen accordingto another exemplary embodiment.

DESCRIPTION OF THE EMBODIMENTS

Exemplary embodiments of the present invention will be described indetail below with reference to the accompanying drawings. It should benoted that the following exemplary embodiments are not intended to limitthe present invention set forth in the claims, and all combinations ofthe features described in the exemplary embodiments are not necessarilyindispensable to the solving means of the present invention. Elements ofone embodiment may be implemented by hardware, firmware, software or anycombination thereof. The term hardware generally refers to an elementhaving a physical structure such as electronic, electromagnetic,optical, electro-optical, mechanical, electro-mechanical parts, etc. Ahardware implementation may include analog or digital circuits, devices,processors, applications specific integrated circuits (ASICs),programmable logic devices (PLDs), field programmable gate arrays(FPGAs), or any electronic devices. The term software generally refersto a logical structure, a method, a procedure, a program, a routine, aprocess, an algorithm, a formula, a function, an expression, etc. Theterm firmware generally refers to a logical structure, a method, aprocedure, a program, a routine, a process, an algorithm, a formula, afunction, an expression, etc., that is implemented or embodied in ahardware structure (e.g., flash memory, ROM, EPROM). Examples offirmware may include microcode, writable control store, micro-programmedstructure. When implemented in software or firmware, the elements of anembodiment may be the code segments to perform the necessary tasks. Thesoftware/firmware may include the actual code to carry out theoperations described in one embodiment, or code that emulates orsimulates the operations. The program or code segments may be stored ina processor or machine accessible medium. The “processor readable oraccessible medium” or “machine readable or accessible medium” mayinclude any medium that may store information. Examples of the processorreadable or machine accessible medium that may store include a storagemedium, an electronic circuit, a semiconductor memory device, a readonly memory (ROM), a flash memory, a Universal Serial Bus (USB) memorystick, an erasable programmable ROM (EPROM), a floppy diskette, acompact disk (CD) ROM, an optical disk, a hard disk, etc. The machineaccessible medium may be embodied in an article of manufacture. Themachine accessible medium may include information or data that, whenaccessed by a machine, cause the machine to perform the operations oractions described above. The machine accessible medium may also includeprogram code, instruction or instructions embedded therein. The programcode may include machine readable code, instruction or instructions toperform the operations or actions described above. The term“information” or “data” here refers to any type of information that isencoded for machine-readable purposes. Therefore, it may includeprogram, code, data, file, etc. All or part of an embodiment may beimplemented by various means depending on applications according toparticular features, functions. These means may include hardware,software, or firmware, or any combination thereof. A hardware, software,or firmware element may have several modules coupled to one another. Ahardware module is coupled to another module by mechanical, electrical,optical, electromagnetic or any physical connections. A software moduleis coupled to another module by a function, procedure, method,subprogram, or subroutine call, a jump, a link, a parameter, variable,and argument passing, a function return, etc. A software module iscoupled to another module to receive variables, parameters, arguments,pointers, etc. and/or to generate or pass results, updated variables,pointers, etc. A firmware module is coupled to another module by anycombination of hardware and software coupling methods above. A hardware,software, or firmware module may be coupled to any one of anotherhardware, software, or firmware module. A module may also be a softwaredriver or interface to interact with the operating system running on theplatform. A module may also be a hardware driver to configure, set up,initialize, send and receive data to and from a hardware device. Anapparatus may include any combination of hardware, software, andfirmware modules.

A configuration of a printing system according to a first exemplaryembodiment of the present invention will be described with reference toFIG. 1. In the following description of the first exemplary embodiment,scanning a document by an optical system moving method using a documentpositioning plate will be defined as “pressing plate reading”. Scanninga document by a feed reading method using an ADF will be defined as “ADFreading”.

In the first exemplary embodiment, a central processing unit (CPU) 114instructs an image forming unit 151 to print an adjustment chart on asheet for adjusting a shift at a printing position. Based on physicalproperties of the sheet, the CPU 114 then determines whether the printedadjustment chart can be scanned by ADF reading. If it is determined thatthe printed adjustment chart can be scanned by ADF reading, the CPU 114controls a screen display so that the user can arbitrarily select eitherof “scanning by ADF reading” and “scanning by pressing plate reading” toperform automatic adjustment of the printing position. On the otherhand, if it is determined that the printed adjustment chart cannot bescanned by ADF reading, the CPU 114 controls a screen display so thatthe user can arbitrarily select “scanning by pressing plate reading” toperform automatic adjustment of the printing position, but not “scanningby ADF reading”. In the first exemplary embodiment, a method foradjusting the printing position is thus appropriately presented to theuser based on the physical properties of the sheet on which theadjustment chart is printed.

A detailed description will be given below.

The printing system according to the present exemplary embodimentincludes a printing apparatus 100 and a personal computer (PC) 101,which is an example of an external apparatus.

The printing apparatus 100 includes an image reading function forreading a document to generate image data, and a print function forprinting an image on a sheet based on the generated image data (i.e.,copy function). The printing apparatus 100 also includes a printfunction for receiving a print job from the PC 101 and printingcharacters and/or images on a sheet based on data for which a printinstruction is received (PC print function). The print functions mayimplement either color or monochrome printing.

A controller unit (control unit) 110 of the printing apparatus 100 isconnected to the PC 101 via a network cable 105. The controller unit 110and the PC 101 are not limited to the configuration of being connectedvia the network cable 105. The controller unit 110 and the PC 101 may beconnected via a local area network (LAN). The controller unit 110 andthe PC 101 may be connected via a wide area network (WAN) such as theInternet, or via a dedicated printer cable. FIG. 1 illustrates anexample of a configuration where one PC 101 is connected to the printingapparatus 100 via the network cable 105. However, it is not limitedthereto. A plurality of PCs 101 may be connected to the printingapparatus 100 via the network cable 105.

For example, the PC 101 generates image data by using applicationsoftware, and transmits the generated image data to the printingapparatus 100. The PC 101 also generates page description language (PDL)data, for example, by using application software and/or a printerdriver. The controller unit 110 rasterizes the PDL data transmitted fromthe PC 101 via the network cable 105 to generate bitmap data. A programused for performing the rasterizing operation is stored in a read-onlymemory (ROM) 112 or a hard disk drive (HDD) 115 to be described below.

In the present exemplary embodiment, the PC 101 is described as anexample of the external apparatus. However, it is not limited thereto.The external apparatus may be a portable information terminal such as apersonal digital assistance (PDA) and a smartphone, a network-connecteddevice, or an external dedicated apparatus.

Next, a block diagram of the printing apparatus 100 according to thepresent exemplary embodiment will be described with reference to FIG. 1.The printing apparatus 100 includes the controller unit 110, a printerengine 150, which is an image output device, the scanner unit 130, whichis an image input device, a feeding unit 140, and an operation unit 120.Such units are electrically connected with each other, and transmit andreceive control commands and data to/from each other.

The controller unit 110 collectively controls an operation of theprinting apparatus 100, and performs input/output control of imageinformation and device information. The controller unit 110 includes theCPU 114, an input/output (I/O) control unit 111, the ROM 112, a randomaccess memory (RAM) 113, and the HDD 115 as a plurality of functionalblocks. Such modules are connected to each other via a system bus 116.

The CPU 114 is a processor for controlling the entire printing apparatus100. The CPU 114 collectively controls access with various connecteddevices based on a control program stored in the ROM 112. The CPU 114also collectively controls various types of processing performed in thecontroller unit 110.

The I/O control unit 111 is a module for performing communicationcontrol with an external network.

The RAM 113 is a readable and writable memory. The RAM 113 also servesas a system work memory used for the CPU 114 operating. The RAM 113stores image data input from the scanner unit 130 and the PC 101,various programs, and setting information.

The ROM 112 is a read-only memory. The ROM 112 is a boot ROM. A bootprogram of the printing system is stored in the ROM 112 in advance.

The HDD 115 mainly stores information (system software) required toactivate and operate the computer, and image data.

If the controller unit 110 includes a nonvolatile RAM (NVRAM) (notillustrated), the system software, image data, and setting informationreceived via the operation unit 120 to be described below may be storedin the NVRAM.

The RAM 113 or the HDD 115 stores a sheet management table 400 formanaging attribute information about sheets to be used for printing bythe printing apparatus 100 in a list form. Details of the sheetmanagement table 400 will be described below with reference to FIG. 4.

The ROM 112 or the HDD 115 stores various control programs to beexecuted by the CPU 114, necessary to perform various types ofprocessing of flowcharts to be described below. The ROM 112 or the HDD115 also stores a display control program for causing a displaying unit(not illustrated) of the operation unit 120 including a user interfacescreen (hereinafter, UI screen) to display various UI screens. The CPU114 reads the programs stored in the ROM 112 or the HDD 115 and loadsthe programs into the RAM 113 to perform various operations according tothe present exemplary embodiment.

The printer engine 150 includes the image forming unit 151 and a fixingunit 155. Further, the image forming unit 151 includes a developing unit152, a photosensitive drum 153, and a transfer belt 154. Details of theimage forming unit 151 and the fixing unit 155 will be described belowwith reference to FIG. 2.

The scanner unit 130 scans an image of a document (sheet) by using anoptical sensor to obtain scan image data. Details of the scanner unit130 will be described below with reference to FIG. 3.

The feeding unit 140 is a unit for feeding sheets from a plurality ofsheet holding units (such as a sheet feeding cassette, a sheet feedingdeck, and a manual tray). Each sheet holding unit can hold a pluralityof types of sheets and can hold a plurality of sheets. The sheets heldin the sheet holding unit are separated one by one from the top andconveyed to the image forming unit 151. The image forming unit 151prints an image on the sheet fed from the sheet holding unit based onimage data input from the scanner unit 130 or the PC 101.

The operation unit 120 corresponds to an example of a user interfaceunit. The operation unit 120 includes the displaying unit (notillustrated) and a key input unit (not illustrated). The operation unit120 has a function for receiving various settings from the user via thedisplaying unit and the key input unit. The operation unit 120 also hasa function for providing information to the user via the displayingunit.

The displaying unit includes a liquid crystal display (LCD) displayingunit and a touch panel sheet including transparent electrodes (may be ofelectrostatic capacity type) attached onto the LCD. The LCD displays anoperation screen as well as a state of the printing apparatus 100. Thekey input unit includes, for example, a start key used to instructexecution of scanning start or copying start, and a stop key used toinstruct an operation stop of scanning or copying in operation.

Next, an example of a sectional view illustrating a configuration of theimage forming unit 151 will be described with reference to FIG. 2.

The image forming unit 151 forms a toner image on the periphery of thephotosensitive drum 153 by using the developing unit 152 according toimage data generated by the controller unit 110.

The developing unit 152 is arranged to oppose the photosensitive drum153. The inside of the developing unit 152 is divided into a developingportion 202 and an agitation portion 203 by a partition wall 201extending in a vertical direction.

A nonmagnetic developing sleeve 204 rotating in the direction of thearrow 241 is arranged in the developing portion 202. A magnet 205 isfixedly arranged inside the developing sleeve 204.

The developing sleeve 204 conveys a developer (e.g., two-componentdeveloper, including magnetic carrier and nonmagnetic toner) taken outby a blade 206. The developing sleeve 204 supplies the developer to thephotosensitive drum 153 in a developing area opposing the photosensitivedrum 153, whereby an electrostatic latent image on the photosensitivedrum 153 is developed. To improve the developing efficiency, i.e., therate of attachment of the toner to the electrostatic latent image, adeveloping bias voltage obtained by superposing an alternating-currentvoltage on a direct-current voltage is applied to the developing sleeve204.

Screws 207 and 208 for agitating the developer are arranged in thedeveloping portion 202 and the agitation portion 203, respectively. Thescrew 207 agitates the developer in the developing portion 202 andconveys the agitated developer. The screw 208 agitates toner 213supplied from a toner discharge port 211 of a toner replenishment tank210 by rotation of a conveyance screw 212, and a developer 214 alreadyexisting in the developing unit 152. The screw 208 conveys the agitateddeveloper to uniformize toner density.

The partition wall 201 has developer passages (not illustrated) forcommunicating the developing portion 202 and the agitation portion 203with each other at near and far ends in FIG. 2. The developer, of whichthe toner density has dropped due to toner consumption by thedeveloping, in the developing portion 202 is moved into the agitationportion 203 through one of the developer passages by conveyance force ofthe screws 207 and 208. The developer of which the toner density isrestored in the agitation portion 203 is moved into the developingportion 202 through the other developer passage.

The photosensitive drum 153 is driven to rotate in the direction of thearrow 242. A primary charging unit 220, the developing unit 152, atransfer unit 221, and a drum cleaner 222 are arranged around thephotosensitive drum 153 in this order in the rotation direction of thephotosensitive drum 153. The primary charging unit 220 uniformly chargesthe photosensitive drum 153. The transfer unit 221 is intended totransfer a developed visible toner image to a sheet.

An image exposure device 223 is arranged above the photosensitive drum153. The image exposure device 223 includes a semiconductor laser, apolygon mirror, and a reflection mirror. The image exposure device 223receives input of a digital pixel signal (video data) corresponding toan image converted into a digital signal by the controller unit 110, andemits a laser beam modulated according to the digital pixel signal.

The image exposure device 223 irradiates the photosensitive drum 153with the laser beam to scan the photosensitive drum 153 in itsgeneratrix direction between the primary charging unit 220 and thedeveloping unit 152. A drum surface of the photosensitive drum 153 isthereby exposed to form an electrostatic latent image. Thephotosensitive drum 153 then rotates and the electrostatic latent imageis developed into a visible toner image by the developing unit 152.

The transfer belt 154 for conveying a sheet in the direction of thearrow 243 is arranged under the photosensitive drum 153. The transferbelt 154 is stretched around a plurality of rollers.

A sheet fed from the feeding unit 140 is conveyed from the right side ofthe transfer belt 154. The sheet is then borne on the transfer belt 154by the action of attraction charging units 230 arranged opposing eachother across the transfer belt 154, and conveyed to the left side of thetransfer belt 154 (in the direction of the arrow 243). When the sheetpasses between the photosensitive drum 153 and the transfer unit 221,the visible toner image developed on the photosensitive drum 153 istransferred to the sheet by the action of the transfer unit 221. Thesheet to which the toner image is transferred is separated from thetransfer belt 154 by a discharging charging unit 231, and conveyed tothe fixing unit 155.

The sheet then passes between a pressure roller (not illustrated) and aheating roller (not illustrated) of the fixing unit 155, whereby thetoner is melted and pressed. As a result, the toner image is fixed tothe sheet. After the transfer of the toner to the sheet, toner remainingon the photosensitive drum 153 is removed by the drum cleaner 222.

Next, an example of sectional views illustrating a configuration of thescanner unit 130 will be described with reference to FIGS. 3A and 3B.

There are two methods for reading an image of a document 301, namely, afeed reading method and an optical system moving method. In the feedreading method, the document 301 is placed on a document stacking unit(also referred to as a document tray) 340. The document 301 is conveyedby an ADF while the image of the document 301 is read at a fixedposition of an optical system. In the optical system moving method, thedocument 301 is placed on a platen glass (document positioning plate)302. The optical system is moved while reading the image of the document301 at a fixed document position.

The scanner unit 130 according to the present exemplary embodiment willbe described assuming a case where both a configuration for scanning thedocument 301 by using the ADF and a configuration for scanning thedocument 301 by using the document positioning plate are includedtherein. However, the present exemplary embodiment is not limitedthereto. In the first exemplary embodiment, the scanner unit 130 mayonly be required to include at least either one of the configuration forscanning the document 301 by using the ADF and the configuration forscanning the document 301 by using the platen glass 302.

An instruction to start a read operation (also referred to as a scanoperation) of the image on the document 301 by the scanner unit 130 isgiven, for example, by the user pressing the start key for instructing ascanning start. Alternatively, an instruction to start the scanoperation may be given, for example, by the user pressing a start buttondisplayed on the displaying unit of the operation unit 120.

The case of reading the image on the document 301 by using the documentpositioning plate will initially be described with reference to FIG. 3A.

If an instruction to start the scan operation is given, to read theimage on the document 301 placed on the platen glass 302, a motor 312 isdriven to once return a first mirror unit 303 and a second mirror unit304 to a position where a home position sensor 305 is disposed. Adocument illumination lamp 306 is turned on to irradiate the document301 with the light. Reflected light from the document 301 is transmittedvia a first mirror 307 in the first mirror unit 303, a second mirror 308in the second mirror unit 304, and a third mirror 309 in the secondmirror unit 304. The reflected light from the third mirror 309 istransmitted through a lens 310 to form an image on a charge coupleddevice (CCD) sensor 311, and input to the CCD sensor 311 as a lightsignal.

The second mirror unit 304 moves at a half speed of the speed (V) of thefirst mirror unit 303, i.e., V/2. The entire surface of the document 301is scanned in such a manner.

In the present exemplary embodiment, the scanner unit 130 is describedto include a reduction optical system with which the reflected lightfrom the document 301 forms an image on the CCD sensor 311. However, itis not limited thereto. The scanner unit 130 may include an equalmagnification optical system with which the reflected light from thedocument 301 forms an image on a contact image sensor (CIS).

Next, the case of reading the image on the document 301 by using the ADFwill be described with reference to FIG. 3B.

If a document (not illustrated) is detected to be set on the documentstacking unit 340 by a document detection sensor (not illustrated)arranged between a pickup roller 322 and a feed roller 323, the scanoperation of the document by using the ADF is started.

If an instruction to start the scan operation is received, then, adocument feeding unit 341 separates the topmost sheet (document) of thedocument bundle by a friction separation method one by one, and conveysthe separated document to a registration roller pair 324. To feed thedocument, the pickup roller 322 moves down on the document bundle and alifting plate moves up to press the document bundle against the feedroller 323 to enter a preliminary operation for document feeding. With amotor (not illustrated) as a driving source, the feed roller 323 and thepickup roller 322 then rotate clockwise to convey the document. Thesecond and subsequent sheets to be conveyed subsequent to the topmostsheet are stopped by a friction piece (not illustrated) and remain onthe document stacking unit 340. The separation of the document isdetected by a separation sensor (not illustrated) arranged downstreamfrom the feed roller 323.

The separated document then passes between guide plates (notillustrated) and conveyed to the registration roller pair 324. When theleading edge of the document reaches the registration roller pair 324,the registration roller pair 324 is stopped. The conveyance by the feedroller 323 loops the document to correct skew, and the document isconveyed to a document conveyance unit 342.

The document conveyance unit 342 rotates a conveyance belt 325, which isstretched around a driving roller 326 and a driven roller 327. Theconveyance belt 325 is pressed against the platen glass 302 by pressurerolls 328. The document conveyed to between the conveyance belt 325 andthe platen glass 302 passes over the platen glass 302 by frictionalforce of the conveyance belt 325.

The document conveyed from the document feeding unit 341 to the documentconveyance unit 342 is conveyed to a predetermined position of theplaten glass 302 by the conveyance belt 325. Then, the driving motor(not illustrated) is stopped to stop conveyance. The scanner unit 130then reads the image of the document by moving the first and secondmirror units 303 and 304 illustrated in FIG. 3A.

After the reading by the scanner unit 130 ends, the document is conveyedto a reversing discharge unit 343 by the conveyance belt 325. At thattime, a reversing flapper 331 for regulating the traveling path of thesheet near an inlet of the reversing discharge unit 343 is controlled bya solenoid (not illustrated) to convey the document to a reversingroller 329. The document is then nipped between the reversing roller 329rotating counterclockwise and a reversing roller 332 opposing thereversing roller 329, and conveyed to a conveyance roller pair 330.

When the trailing edge of the document reaches a point after passingthrough a discharge flapper 333, the discharge flapper 333 turnsclockwise and the reversing roller 329 makes reverse rotation, i.e.,clockwise. This starts switchback conveyance of the document. In thisway, the document conveyed by the clockwise rotation of the reversingroller 329 is discharged to a document discharge unit 344. When there isa subsequent document, the subsequent document is conveyed to thepredetermined position by the rotation of the conveyance belt 325 likethe preceding document. The image of the document stopped at the readingposition according to the stop of the driving motor is then read by thescanner unit 130 by moving the first and second mirror units 303 and 304illustrated in FIG. 3A. During the execution of such a scan operation,the preceding document is reversed by the reversing discharge unit 343,which operates independently, and conveyed to the document dischargeunit 344.

In the example illustrated in FIG. 3B, a method is described in whichthe document 301 is conveyed to the position at which the document 301is read by using the document positioning plate, and the conveyance ofthe document 301 is stopped for scanning (optical system moving method),when the image of the document 301 is read by using the ADF. However, itis not limited thereto. For example, the method for reading the image ofthe document 301 by using the ADF may include conveying the document 301at constant speed while scanning the document 301 by the scanner unit130, with the first and second mirror units 303 and 304 fixed at aposition without moving them (feed reading method).

To scan the back surface of the document 301 by using the ADF, after thefront surface of the document 301 is scanned, the document 301 may bereversed and conveyed to successively scan the back surface of thedocument 301 (referred to as two-sided reversing reading).Alternatively, if the scanner unit 130 includes two reading sensorsabove and below the conveyance path of the document 301, the front andback surfaces of the document 301 may be simultaneously scanned by feedreading (referred to as two-sided simultaneous reading).

In the following description of the present exemplary embodiment,scanning the document 301 by the “optical system moving method using thedocument positioning plate” will be defined as “pressing plate reading”.Scanning the document 301 by the “feed reading method using the ADF”will be defined as “ADF reading”.

Next, details of the sheet management table 400 for managing theattribute information about the sheets used for printing in the printingapparatus 100 will be described with reference to FIG. 4.

Examples of the sheets used for printing in the printing apparatus 100include sheets to be used normally, sheets evaluated by printer makers,and user-defined sheets, which are standard sheets or evaluated sheetsof which attribute information is customized by the user. The attributeinformation about such the plurality of sheets is stored in the RAM 113or the HDD 115 in a list form using the sheet management table 400. Thepieces of data registered in the sheet management table 400 are digitalinformation such as of Extensible Markup Language (XML) andcomma-separated values (CSV). Software modules can read and write thesheet management table 400 stored in the RAM 113 or the HDD 115.

Next, details of the data registered in the sheet management table 400(attribute information about sheets) will be described below.

A sheet name 411 is information for identifying the sheets used forprinting from each other.

A sheet length in a sub scanning direction 412, a sheet length in a mainscanning direction 413, grammage of a sheet 414, and a surface propertyof the sheet 415 are physical properties of the sheet used for printing.The surface property of the sheet 415 is an attribute for indicating aphysical property of the surface of the sheet. Examples include “coated”which indicates the application of surface coating for improvedglossiness, and “embossed” which indicates the presence of surfaceprojections and depressions.

Color of a sheet 416 is an attribute for indicating the background colorof the sheet. Preprinted paper 417 is information for identifyingwhether the sheet used for printing is preprinted paper.

The printing apparatus 100 adjusts a shift in the printing position withrespect to a sheet at the time of execution of printing so that an imageis printed at an ideal printing position. The amount of shift in theprinting position with respect to the front surface of a sheet 420 isinformation indicating the amount of positional shift from an idealprinting position on the front surface of the sheet. The amount of shiftin the printing position with respect to the back surface of a sheet 421is information indicating the amount of positional shift from an idealprinting position on the back surface of the sheet.

Examples of the amounts of shift in the printing position 420 and 421include the amount of shift in the printing position in the sub scanningdirection (hereinafter, referred to as the amount of shift in a leadposition) with respect to the sheet. The lead position refers to thestart position of printing an image, with the leading edge of theadjustment chart in the conveyance direction of the sheet as the origin.An initial value of the lead position is zero. When the amount of shiftin the lead position is adjusted, the radiation start timing of thelaser beam from the image exposure device 223 onto the photosensitivedrum 153 is adjusted. As a result, the start position of printing theimage with respect to the leading edge of the adjustment chart in theconveyance direction of the sheet can be changed.

Examples of the amounts of shift in the printing position 420 and 421include the amount of shift in the printing position in the mainscanning direction (hereinafter, referred to as the amount of shift in aside position) with respect to the sheet. The side position refers tothe start position of printing an image, with the left edge of theadjustment chart in the conveyance direction of the sheet as the origin.An initial value of the side position is zero. When the amount of shiftin the side position is adjusted, the radiation start timing of thelaser light from the image exposure device 223 onto the photosensitivedrum 153 is adjusted. As a result, the start position of printing theimage with respect to the left edge of the adjustment chart in theconveyance direction of the sheet can be changed.

Examples of the amounts of shift in the printing position 420 and 421include the amount of shift in an image length (magnification to anideal length) in the sub scanning direction (hereinafter, referred to assub scanning magnification) and the amount of shift in an image length(magnification to an ideal length) in the main scanning direction(hereinafter, referred to as main scanning magnification). Initialvalues of the sub scanning magnification and the main scanningmagnification are zero. The sub scanning magnification is adjusted bycontrolling a driving speed of the transfer belt 154. On the other hand,the main scanning magnification is adjusted by controlling a clockfrequency of the laser beam when the image exposure device 223 modulatesthe digital image signal into the laser beam.

The amounts of shift in the printing position 420 and 421 are calculatedby the scanner unit 130 scanning an adjustment chart on whichpredetermined marks are printed, and detecting the positions of themarks on the adjustment chart. Details of the adjustment chart on whichthe predetermined marks are printed will be described below withreference to FIG. 6.

As described above, it is described that the amounts of shift in theprinting position 420 and 421 are adjusted, for example, by adjustingthe radiation timing of the laser beam. However, it is not limitedthereto. A shift in the printing position may be adjusted by shiftingthe image to be printed on the sheet itself by a predetermined amountduring printing. When the amounts of shift in the printing position areadjusted, the user may be allowed to arbitrarily designate the amountsof shift of the image to be printed on the sheet.

The user can edit the attribute information about the sheets registeredin the sheet management table 400 and additionally register a new sheetinto the sheet management table 400 by using an editing screen 500illustrated in FIG. 5A. For example, the editing screen 500 is displayedon the displaying unit of the operation unit 120 or a monitor (notillustrated) of the PC 101.

A sheet selected by the user via the editing screen 500 is highlighted.In the example illustrated in FIG. 5A, the sheet “XYZ paper co., color81” is highlighted. The user can press a button 501 on the editingscreen 500 to add a new sheet to be registered in the sheet managementtable 400. The user can press a button 502 on the editing screen 500 toedit the attribute information about the selected sheet (highlightedsheet). If the button 501 or 502 is pressed by the user, an editingscreen 510 illustrated in FIG. 5B is called. For example, the editingscreen 510 is displayed on the displaying unit of the operation unit 120or the monitor (not illustrated) of the PC 101.

On the editing screen 510, the user can input respective pieces of dataabout, for example, the sheet name, sheet length in the sub scanningdirection, sheet length in the main scanning direction, grammage,surface property, color, and preprinted paper. The surface property isselected from a list of surface properties that can be supported by theprinting apparatus 100. The color is selected from a list of colorsregistered in advance. If the user inputs the pieces of data and thenpresses a button 511 on the editing screen 510, the data (attributeinformation about the sheet) input at that time is finalized andregistered in the sheet management table 400.

On the editing screen 510, the user can input attribute informationabout the sheet name, sheet length in the sub scanning direction, sheetlength in the main scanning direction, grammage, surface property, andcolor. For the surface property, the user selects one from the list ofsurface properties that can be supported by the printing apparatus 100.For the color, the user can select arbitrary one from the list of colorsregistered in advance. On the editing screen 510, the user can inputinformation about whether the sheet to be edited is preprinted paper.

If the user presses an end editing button 511 on the editing screen 510,the sheet attributes input at that time are finalized and registered inthe sheet management table 400.

The user can press a button 503 on the editing screen 500 to perform aseries of processing for adjusting the printing position with respect tothe selected sheet (highlighted sheet). Details of the series ofprocessing for adjusting the printing position will be described belowwith reference to FIGS. 8 to 10.

Next, an example of a schematic diagram illustrating an adjustment chartused to adjust the printing position will be described with reference toFIG. 6.

Image data for an adjustment chart 601 is stored in the RAM 113 or theHDD 115. When printing the adjustment chart 601, the image data on theadjustment chart 601 is read from the RAM 113 or HDD 115 and transferredto the printer engine 150.

When the printing position on the front surface is adjusted with respectto a sheet, the marks 620 are printed at specific positions (forexample, on four corners) of the front surface of the sheet. When theprinting position on the back is adjusted with respect to the sheet, themarks 620 are printed at specific positions (e.g., on four corners) ofthe back surface of the sheet. The marks 620 are formed by using tonerof a color that has a large difference in reflectance with respect to anormal sheet (e.g., black toner). In this way, four marks 620 areprinted on the front surface and four on the back surface of theadjustment chart 601 (i.e., a total of eight marks 620).

An image 610 for identifying the conveyance direction of the adjustmentchart 601 and an image 612 for identifying the front or back surface ofthe adjustment chart 601 are printed on the front surface of theadjustment chart 601. An image 611 for identifying the conveyancedirection of the adjustment chart 601 and an image 613 for identifyingthe front or back surface of the adjustment chart 601 are printed on theback surface of the adjustment chart 601.

In other words, to position two-sided images when two-sided printing isperformed, the images 610 and 612 are printed on the front surface ofthe adjustment chart 601, and the images 611 and 613 are printed on theback surface of the adjustment chart 601. On the other hand, to adjustthe printing position when one-sided printing is performed, at least theimages 610 and 612 are printed on the front surface of the adjustmentchart 601.

The images 610 and 611 for identifying the conveyance direction of theadjustment chart 601 have only to be printed when the adjustment chart601 is scanned by ADF reading. When the adjustment chart 601 is scannedby pressing plate reading, the images 610 and 611 do not need to beprinted.

As illustrated in FIG. 6, examples of the images 610 and 611 are arrowswith which the user can identify the conveyance direction of theadjustment chart 601. On the other hand, examples of the images 612 and613 are characters with which the user can identify the front and backsurfaces of the adjustment chart 601.

The marks 620, if printed at ideal positions, are arranged to be printedat positions with predetermined distances from the edges of theadjustment chart 601. The positions of the marks 620 printed on thefront surface of the adjustment chart 601 are measured to calculate (orobtain) the amount of shift in the printing position on the frontsurface of the sheet.

The position of the marks 620 printed on the back surface of theadjustment chart 601 is measured to calculate (or obtain) the amount ofshift in the printing position on the back surface of the sheet.

Relative positions between the respective marks 620 printed on the frontand back surfaces of the adjustment chart 601 may be measured tocalculate (or obtain) the amounts of shifts in the printing position onthe back surface with respect to the printing position on the frontsurface, or the amounts of shifts in the printing position on the frontsurface with respect to the printing position on the back surface.

Next, a case of adjusting the printing position by using the adjustmentchart 601 will be described below with reference to FIG. 6.

To measure the positions of the marks 620 on the front and back surfacesof the adjustment chart 601, portions (a) to (j) on the front surface ofthe adjustment chart 601 and portions (k) to (r) on the back surface ofthe adjustment chart 601 are measured, respectively.

The portion (a) is the length of the adjustment chart 601 in the subscanning direction. The portion (b) is the length of the adjustmentchart 601 in the main scanning direction. The ideal length of theportion (a) is the sheet length in the sub scanning direction 412registered in the sheet management table 400. The ideal length of theportion (b) is the sheet length in the main scanning direction 413registered in the sheet management table 400. The lengths of theportions (c) to (r) are the distances from the respective marks 620 tothe closest edges of the adjustment chart 601.

The lengths of the portions (a) to (r) may be measured by a manualmeasurement method or an automatic calculation method. In the manualmeasurement method, the user actually measures the lengths of theportions (a) to (r) of the adjustment chart 601 by using a ruler.

On the other hand, in the automatic calculation method, the scanner unit130 scans the adjustment chart 601. Then, the CPU 114 analyzes the imagedata generated by reading the images of the adjustment chart 601. As aresult of the analysis, the CPU 114 detects the edges of the adjustmentchart 601 and the edges of the marks 620 (i.e., the borders between thebackground of the adjustment chart 601 and the marks 620) based on adifference in density. Then, the CPU 114 calculates the lengths of theportions (a) to (r) from the detected edges of the adjustment chart 601and the edges of the marks 620. Details of the processing for analyzingthe image data on the adjustment chart 601 will be described below withreference to FIG. 8.

Next, a method for calculating the amounts of shift in the printingposition based on the measured positions of the marks 620 will bedescribed with reference to FIG. 7.

FIG. 7 illustrates a table 700 which defines measurement value 710,ideal value 711, and the amount of shift in the printing position 712 ofthe “lead position”, “side position”, “main scanning magnification”, and“sub scanning magnification” on the front and back surfaces of theadjustment chart 601. The table 700 is stored in the RAM 113 or the HDD115.

For example, the measurement value 710 of the “lead position” on thefront surface of the adjustment chart 601 is calculated from theactually measured values of the portions (c) and (e) illustrated in FIG.6 by using the formula illustrated in the table 700. More specifically,the lead position is an average of the distances from the leading edgeof the adjustment chart 601 in the conveyance direction of the sheet tothe respective corresponding marks 620.

For example, the measurement value 710 of the “side position” on thefront surface of the adjustment chart 601 is calculated from theactually measured values of the portions (f) and (j) illustrated in FIG.6 by using the formula illustrated in the table 700. More specifically,the side position is an average of the distances from the left edge ofthe adjustment chart 601 in the conveyance direction of the sheet to therespective corresponding marks 620.

For example, the measurement value 710 of the “main scanningmagnification” on the front surface of the adjustment chart 601 iscalculated from the actually measured values of the portions (b), (d),(f), (h), and (j) illustrated in FIG. 6 by using the formula illustratedin the table 700. More specifically, the main scanning magnification isan average of the distances between the marks 620 arranged on the samescanning lines in the main scanning direction.

For example, the measurement value 710 of the “sub scanningmagnification” on the front surface of the adjustment chart 601 iscalculated from the actually measured values of the portions (a), (c),(e), (g), and (i) illustrated in FIG. 6 by using the formula illustratedin the table 700. More specifically, the sub scanning magnification isan average of the distances between the marks 620 arranged on the samescanning lines in the sub scanning direction.

As illustrated in the table 700, the ideal values 711 of the “leadposition” and the “side position” are both 1 cm. In other words, themarks 620 can ideally be printed at positions 1 cm from the respectivecorresponding edges of the adjustment chart 601.

As illustrated in the table 700, the ideal value 711 of the “mainscanning magnification” is a value obtained by subtracting 2 cm from thesheet length in the main scanning direction of each sheet registered inthe sheet management table 400. Similarly, the ideal value 711 of the“sub scanning magnification” is a value obtained by subtracting 2 cmfrom the sheet length in the sub scanning direction of each sheetregistered in the sheet management table 400.

As illustrated in the table 700, the amounts of shift in the printingposition 712 in terms of the “lead position”, “side position”, “mainscanning magnification”, and “sub scanning magnification” are calculatedby using the respective corresponding measurement values 710 and idealvalues 711.

More specifically, the amounts of shift in the printing position 712 ofthe “lead position” and the “side position” are calculated bysubtracting the ideal values 711 from the measurement values 710 (inunits of “mm”). The amounts of shift in the printing position 712 of the“main scanning magnification” and the “sub scanning magnification” arecalculated by subtracting the ideal values 711 from the measurementvalues 710, divided by the ideal values 711 (in units of “%”).

The amounts of shift in the printing position 712 calculated above areregistered in the sheet management table 400 as the attributeinformation about the sheet.

Next, a method for detecting image edges of the adjustment chart 601 andimage edges of the marks 620 based on image data 800 generated byscanning the adjustment chart 601 by the scanner unit 130 will bedescribed with reference to FIGS. 8A and 8B.

In the example illustrated in FIGS. 8A and 8B, the adjustment chart 601is assumed to be scanned by pressing plate reading, with a backing sheet(not illustrated) of a black image put over the adjustment chart 601that is placed on the platen grass 302. To scan the adjustment chart 601by ADF reading, an adjustment chart (not illustrated) obtained byforming black marks in contact with part of the edges of the adjustmentchart 601 may be scanned instead of the scanning with the backing sheet.In such a case, the same description applies.

Part of the image data 800 generated by scanning the adjustment chart601 by pressing plate reading will be described with reference to FIG.8A.

An area 801 is an image data area of the image data 800 based on thebacking sheet (not illustrated). An area 802 is an image data area ofthe image data 800 based on the background of the adjustment chart 601.Areas 803 are image data areas of the image data 800 based on the marks620 of the adjustment chart 601. Edges 810 are the edges of the area 802(i.e., the image edges of the adjustment chart 601). Edges 812 are theedges of the areas 803 (i.e., the image edges of the marks 620).

Analysis ranges 811 are ranges where the image data 800 is analyzedtherein (in other words, ranges of interest of analysis processing). Theimage data 800 is analyzed by measuring changes in density in the mainscanning direction and the sub scanning direction from the image edgesof the image data 800 in units of pixels. The CPU 114 then detects theareas 801, 802, and 803, and the edges 810 and 812 from the measurementresult. The units of measurement may be smaller than or greater thanpixels. The reading may be performed at regular pitches or in a thinnedmanner.

Next, an example of an analysis result of the image data 800 in ananalysis range 811 will be described with reference to FIG. 8. Themeasurement of the density of the image data 800 in the analysis range811 starts at an image edge of the image data 800.

First, the CPU 114 detects the density of the area 801 (corresponding toa section (A) in FIGS. 8A and 8B). Then, the CPU 114 detects the densityof the area 802 lying between the areas 801 and 803 (corresponding to asection (B) in FIGS. 8A and 8B). Then, the CPU 114 detects the densityof the area 803 lying between the areas 802 and 812 (corresponding to asection (C) in FIGS. 8A and 8B). Then, the CPU 114 detects the densityof the area 802 lying between the areas 803 (corresponding to a section(D) in FIGS. 8A and 8B). Then, the CPU 114 detects the density of thearea 803 lying between the areas 802 (corresponding to a section (E) inFIGS. 8A and 8B). Then, the CPU 114 detects the density of the area 802lying between the areas 803 and 801 (corresponding to a section (F) inFIGS. 8A and 8B). Then, the CPU 114 detects the density of the area 801(corresponding to a section (G) in FIGS. 8A and 8B).

Based on these measurement results, the CPU 114 calculates the ranges ofthe images printed on the adjustment chart 601 from the measuredpositions of the sections (A) to (G) of the image data 800. The CPU 114further detects that the areas 803 in the sections (C) and (E) are basedon the density of the marks 620 printed on the printing apparatus 601.The CPU 114 further detects that the areas 801 in the sections (A) and(G) are based on the density of the background of the backing sheet (notillustrated).

From such a detection result, the CPU 114 detects a point where thedensity switches between the sections (A) and (B) as an edge 810 (i.e.,image edge (left edge) of the adjustment chart 601). The CPU 114 furtherdetects a point where the density switches between the sections (B) and(C) as an edge 812 (i.e., image edge (left edge) of the left mark 620).The CPU 114 further detects a point where the density switches betweenthe sections (C) and (D) as an edge 812 (i.e., image edge (right edge)of the left mark 620). The CPU 114 further detects a point where thedensity switches between the sections (D) and (E) as an edge 812 (i.e.,image edge (left edge) of the right mark 620). The CPU 114 furtherdetects a point where the density switches between the sections (E) and(F) as an edge 812 (i.e., image edge (right edge) of the right mark620). The CPU 114 further detects a point where the density switchesbetween the sections (F) and (G) as an edge 810 (i.e., image edge (rightedge) of the adjustment chart 601).

Based on the above-described detection result, the CPU 114 thencalculates the distance from the image edge (left edge) of theadjustment chart 601 to the image edge (left edge) of the left mark 620as the length of the portion (c) of the adjustment chart 601.

The CPU 114 further calculates the distance from the image edge (rightedge) of the right mark 620 to the image edge (right edge) of theadjustment chart 601 as the length of the portion (g) of the adjustmentchart 601.

The CPU 114 further calculates the distance from the image edge (leftedge) of the adjustment chart 601 to the image edge (right edge) of theadjustment chart 601 as the length of the portion (a) of the adjustmentchart 601.

While the method of calculating the lengths of the portions (c) and (g)of the adjustment chart 601 is described above, the lengths of theportions (e) and (i), (d) and (f), and (h) and (j) of the adjustmentchart 601 can also be calculated by a similar way. While the method forcalculating the length of the portion (a) of the adjustment chart 601 isdescribed above, the length of the portion (b) of the adjustment chart601 can also be calculated by a similar way.

In this way, since the image edges of the adjustment chart 601 and theimage edges of the marks 620 are detected, the CPU 114 can automaticallycalculate the lengths of the portions (a) to (r) of the adjustment chart601.

In the first exemplary embodiment, the CPU 114 instructs the imageforming unit 151 to print the adjustment chart 601 on a sheet used foradjusting a shift in the printing position. Then, the CPU 114 determineswhether the printed adjustment chart 601 can be scanned by ADF reading,based on the physical properties of the sheet. If the CPU 114 determinesthat the printed adjustment chart 601 can be scanned by ADF reading, theCPU 114 controls a screen display so that the user can arbitrarilyselect either of “scanning by ADF reading” and “scanning by pressingplate reading” to perform automatic adjustment of the printing position.On the other hand, if the CPU 114 determines that the printed adjustmentchart 601 cannot be scanned by ADF reading, the CPU 114 controls ascreen display so that the user can arbitrarily select “scanning bypressing plate reading” to perform automatic adjustment of the printingposition, but not “scanning by ADF reading”. In the first exemplaryembodiment, a method for adjusting the printing position is thusappropriately presented to the user based on the physical properties ofthe sheet on which the adjustment chart 601 is printed.

A detailed description will be given below.

A series of processing by which the printing apparatus 100 according tothe first exemplary embodiment adjusts the printing position will bedescribed with reference to the flowchart illustrated in FIG. 9. Suchprocessing is performed by the CPU 114 of the controller unit 110executing a control program that is read from the ROM 112 or the HDD 115and loaded into the RAM 113. The processing in FIG. 9 is started, forexample, in a state where the editing screen 500 illustrated in FIG. 5Ais displayed on the displaying unit of the operation unit 120.

In step S901, the CPU 114 receives selection of a sheet for adjustingthe printing position from the user on the editing screen 500. Then, theprocessing proceeds to step S902. If the user presses the button 503with a sheet highlighted on the editing screen 500, the highlightedsheet is selected as the sheet for adjusting the printing position.

In step S902, the CPU 114 obtains the physical properties (e.g., thesheet length in the sub scanning direction 412, the sheet length in themain scanning direction 413, the grammage of the sheet 414, and thesurface property of the sheet 415) of the sheet selected in step S901.Then, the processing proceeds to step S903. In addition, the CPU 114obtains the physical properties of the sheet selected in step S901 byreferring to the attribute data (sheet lengths, grammage, and surfaceproperty) of the sheet registered in the sheet management table 400.

In step S903, the CPU 114 determines whether the sheet selected in stepS901 (i.e., the sheet for adjusting the printing position) can bescanned by ADF reading. The CPU 114 determines whether the sheet can bescanned by ADF reading, based on the physical properties of the sheetobtained in step S902.

For example, if the length of the sheet in the main scanning directionis greater than a maximum guide width of the document stacking unit 340of the ADF, the sheet cannot be set on the document stacking unit 340.Therefore, the CPU 114 determines that the sheet cannot be scanned byADF reading.

A specific example will be described here. The length of a sheet of “A3size” in the main scanning direction is 297 mm. If the document stackingunit 340 has a maximum guide width of 297 mm, a sheet of “12×18 size”having a length of 304.8 mm in the main scanning direction or a sheet of“13×19 size” having a length of 330.2 mm in the main scanning directionis unable to be set on the document stacking unit 340. A sheet of“12×18” size and a sheet of “13×19” size can be stored in a sheetholding unit such as a sheet feeding cassette, a sheet feeding deck, anda manual tray, and therefore images can be printed on such sheets. Thus,there are sizes of sheets that are printable by the image forming unit151 but not able to be scanned by ADF reading.

For example, if a sheet has a grammage beyond the range of grammagesupported as being capable of scanning by ADF reading, the sheetcorresponds to a parameter condition that can cause a jam on theconveyance path of the ADF. Therefore, the CPU 114 determines that thesheet cannot be scanned by ADF reading.

A specific example will be described here. If the range of grammagesupported as being capable of scanning by ADF reading is 64 g/m² to 150g/m², a sheet having a grammage of 181 g/m² cannot be scanned by ADFreading.

For example, if the type of the sheet is “tab paper” or “cardboard”, thestiffness of the sheet is so high (i.e., the sheet is so stiff) that ajam can occur on the conveyance path of the ADF. For example, if thetype of the sheet is “overhead projector (OHP) sheet” or “transparentfilm”, the stiffness of the sheet is so low (i.e., the sheet is so soft)that a jam can occur on the conveyance path of the ADF. If the type ofthe sheet is a specific one (e.g., “tab paper”, “cardboard”, “OHPsheet”, and “transparent film”), the CPU 114 determines that the sheetcannot be scanned by ADF reading.

As a result of the determination in step S903, if the CPU 114 determinesthat the sheet can be scanned by ADF reading (YES in step S903), theprocessing proceeds to step S904. On the other hand, if the CPU 114determines that the sheet cannot be scanned (NO in step S903), theprocessing proceeds to step S905.

In step S904, the CPU 114 displays a selection screen 1010 (alsoreferred to as a first reception screen) illustrated in FIG. 10A on thedisplaying unit of the operation unit 120. Then, the processing proceedsto step S906. The selection screen 1010 is a screen for allowing theuser to select one from among performing automatic adjustment of theadjustment chart 601 by pressing plate reading 1001, performingautomatic adjustment by ADF reading 1002, and manual adjustment 1003 asa method for adjusting the printing position.

In step S905, the CPU 114 displays a selection screen 1020 (alsoreferred to as a second reception screen) illustrated in FIG. 10B on thedisplaying unit of the operation unit 120. Then, the processing proceedsto step S906. The selection screen 1020 is a screen for allowing theuser to select either performing automatic adjustment of the adjustmentchart 601 by pressing plate reading 1001 or manual adjustment 1003 as amethod for adjusting the printing position. Unlike the selection screen1010, the selection screen 1020 is configured so that the user cannotgive an instruction to perform automatic adjustment of the adjustmentchart 601 by ADF reading. While FIG. 10B illustrates the selectionscreen 1020 where the button 1002 is hidden, the button 1002 may bedisplayed by a gray-out display. A warning message (not illustrated)that “the automatic adjustment of the adjustment chart 601 cannot beperformed by ADF reading” may be further displayed over the selectionscreen 1020.

In step S906, the CPU 114 determines whether a method for adjusting theprinting position is selected by the user on either of the selectionscreens 1010 and 1020. If any one of the buttons 1001, 1002, and 1003 onthe selection screen 1010 and the buttons 1001 and 1003 on the selectionscreen 1020 is pressed (YES in step S906), the processing proceeds tostep S907. If none of the buttons 1001, 1002, and 1003 on the selectionscreen 1010 and the buttons 1001 and 1003 on the selection screen 1020is pressed (NO in step S906), the processing of step S906 is repeated.

In step S907, the CPU 114 determines whether manual adjustment isselected by the user as the method for adjusting the printing position.If the button 1003 on the selection screen 1010 or the button 1003 onthe selection screen 1020 is pressed (YES in step S907), the processingproceeds to step S909. On the other hand, if the button 1001 or 1002 onthe selection screen 1010 or the button 1001 on the selection screen1020 is pressed (NO in step S906), the processing proceeds to step S908.

In step S908, the CPU 114 determines whether automatic adjustment(reading by ADF) is selected by the user as the method for adjusting theprinting position. If the button 1002 on the selection screen 1010 ispressed (YES in step S908), the processing proceeds to step S1500. Instep S1500, the CPU 114 performs automatic adjustment of the printingposition by scanning the adjustment chart 601 by ADF reading. Then, theprocessing proceeds to step S912. Details of the processing of stepS1500 will be described below with reference to FIG. 12.

On the other hand, if the button 1001 on the selection screen 1010 orthe button 1001 on the selection screen 1020 is pressed (NO in stepS908), the CPU 114 determines it to be “NO” and the processing proceedsto step S1100. In step S1100, the CPU 114 performs automatic adjustmentof the printing position by scanning the adjustment chart 601 bypressing plate reading. Then, the processing proceeds to step S912.Details of the processing of step S1100 will be described below withreference to FIG. 11.

In step S909, the CPU 114 instructs the image forming unit 151 to printthe adjustment chart 601 on the sheet selected in step S901. Receivingthe print instruction, the image forming unit 151 prints the adjustmentchart 601 on the selected sheet fed from the feeding unit 140. The sheeton which the adjustment chart 601 is printed is discharged from theprinting apparatus 100. After the processing of step S909, theprocessing proceeds to step S910.

In step S910, the CPU 114 receives input of the lengths (actuallymeasured values) of the portions (a) to (r) manually measured from theuser on the editing screen 510 illustrated in FIG. 5B. Then, theprocessing proceeds to step S911.

In step S911, the CPU 114 calculates the amounts of shift in theprinting position 712 based on the lengths of the portions (a) to (r)input in step S910. Then, the processing proceeds to step S912. Theamounts of shift in the printing position 712 are calculated by usingthe formulas described above with reference to FIG. 7.

In step S912, the CPU 114 registers the amounts of shift in the printingposition 712 into the sheet management table 400 as those with respectto the sheet selected on the editing screen 500. For example, in stepS912, the lead positions, side positions, main scanning magnifications,and sub scanning magnifications are registered as information indicatingthe amounts of shift in the printing position on the front surface 420and the amounts of shift in the printing position on the back surface421 with respect to the sheet selected in step S901. After theprocessing of step S912, the series of processing related to FIG. 9ends.

That is the details of the series of processing for adjusting theprinting position (FIG. 9).

Next, a series of processing for performing automatic adjustment of theprinting position by scanning the adjustment chart 601 by pressing platereading will be described with reference to the flowchart illustrated inFIG. 11. Such processing is performed by the CPU 114 of the controllerunit 110 executing a control program that is read from the ROM 112 orthe HDD 115 and loaded into the RAM 113.

In step S1101, the CPU 114 displays a designation screen 1200illustrated in FIG. 12 on the displaying unit of the operation unit 120.Then, the processing proceeds to step S1102. The designation screen 1200is a screen for receiving designation of the number of adjustment charts601 to print for adjusting the printing position from the user. Aplurality (e.g., ten) of adjustment charts 601 can be scanned and theamounts of shift in the printing position can be averaged to increasethe accuracy of the amounts of shift in the printing position.Therefore, the user designates, on the designation screen 1200, thenumber of adjustment charts 601 to print for adjusting the printingposition.

In step S1102, the CPU 114 receives the designation of the number ofadjustment charts 601 to print from the user on the designation screen1200. Then, the processing proceeds to step S1103.

In step S1103, the CPU 114 instructs the image forming unit 151 to printthe adjustment charts 601 as many as designated in step S1102. At thattime, the image data of the adjustment chart 601 is read from the RAM113 or the HDD 115 and transferred to the printer engine 150. Receivingthe print instruction, the image forming unit 151 prints the adjustmentchart 601 on the sheets fed from the feeding unit 140 (i.e., the sheetselected in step S901). The sheets on which the adjustment chart 601 isprinted are discharged from the printing apparatus 100. After theprocessing of step S1103, the processing proceeds to step S1104.

In step S1104, the CPU 114 displays a confirmation screen 1310 (referredto as a first confirmation screen) illustrated in FIG. 13A on thedisplaying unit of the operation unit 120. The confirmation screen 1310is a screen for prompting the user to set an adjustment chart 601 on theplaten glass 302 (document positioning plate) so that the images on thefront surface of the adjustment chart 601 are read. If the user pressesa button 1311 (start reading button) on the confirmation screen 1310,the processing proceeds to step S1105.

In step S1105, the CPU 114 instructs the scanner unit 130 to scan theadjustment chart 601 printed in step S1103 by pressing plate reading.Then, the processing proceeds to step S1106.

In step S1106, the CPU 114 performs image analysis on image datagenerated by scanning the adjustment chart 601. The CPU 114 performs theimage analysis on the image data by the method described above withreference to FIGS. 8A and 8B. Based on the image analysis, the CPU 114detects the image edges of the adjustment chart 601 and the image edgesof the marks 620, focusing on a difference in density. Then, theprocessing proceeds to step S1107.

In step S1107, the CPU 114 determines whether the image edges of theadjustment chart 601 and the image edges of the marks 620 aresuccessfully detected as a result of the detection processing in stepS1106. If the CPU 114 determines that the detection has succeeded (YESin step S1107), the processing proceeds to step S1108. On the otherhand, if the CPU 114 determines that the detection has failed (NO instep S1107), the processing proceeds to step S1116. Examples of the casewhere the CPU 114 determines it to be “NO” in step S1107 include a casewhere a difference in density between the background of the sheet onwhich the adjustment chart 601 is printed and the marks 620 is so smallthat the image edges of the marks 620 fail to be properly detected.

In step S1108, the CPU 114 determines whether the back surface of theadjustment chart 601 is scanned by the scan processing in step S1105.The CPU 114 can determine which side of surface of the adjustment chart601 is scanned, the front surface or back surface, by performing imageanalysis on the image data based on the image 612 or 613 for identifyingthe front or back surface of the adjustment chart 601. If the CPU 114determines that the back surface is scanned (YES in step S1108), theprocessing proceeds to step S1111. On the other hand, if the CPU 114determines that the back surface is not scanned (NO in step S1108), theprocessing proceeds to step S1109.

In step S1109, the CPU 114 calculates the lengths of the portions (a) to(j) illustrated in FIG. 6 from the image edges of the adjustment chart601 and the image edges of the marks 620 detected in step S1106. Then,the processing proceeds to step S1110.

In step S1110, the CPU 114 displays a confirmation screen 1320 (referredto as a second confirmation screen) illustrated in FIG. 13B on thedisplaying unit of the operation unit 120. The confirmation screen 1320is a screen for prompting the user to set the adjustment chart 601 onthe platen glass 302 (document positioning plate) so that the images onthe back surface of the adjustment chart 601 are read. If the userpresses a button 1321 (start reading button) on the confirmation screen1320, the processing returns to step S1105 and the CPU 114 continues thesubsequent processing.

In step S1111, the CPU 114 calculates the lengths of the portions (k) to(r) illustrated in FIG. 6 from the image edges of the adjustment chart601 and the image edges of the marks 620 detected in step S1106. Then,the processing proceeds to step S1112.

In step S1112, the CPU 114 calculates the amounts of shift in theprinting position 712 based on the lengths of the portions (a) to (j)calculated in step S1109 and the lengths of the portions (k) to (r)calculated in step S1111. Then, the processing proceeds to step S1113.The amounts of shift in the printing position 712 are calculated byusing the formulas described above with reference to FIG. 7.

In step S1113, the CPU 114 determines whether the amounts of shift inthe printing position have been calculated for the number of printedadjustment charts 601 (i.e., the number of adjustment charts 601designated in step S1102). The CPU 114 performs the determinationprocessing of step S1113 by storing the number of times of processing ofstep S1112 into the HDD 115 or the RAM 113 as a counter, and comparingthe value of the stored counter with the number of adjustment charts 601designated in step S1102. As a result of the determination in stepS1113, if the CPU 114 determines it to be “YES” (YES in step S1113), theprocessing proceeds to step S1115. On the other hand, if the CPU 114determines it to be “NO” (NO in step S1113), the processing proceeds tostep S1114.

In step S1114, the CPU 114 displays the confirmation screen 1310 (firstconfirmation screen) illustrated in FIG. 13A on the displaying unit ofthe operation unit 120. If the user presses the button 1311 (startreading button) on the confirmation screen 1310, the processing returnsto step S1105 and the CPU 114 continues the subsequent processing.

In step S1115, the CPU 114 calculates average values of the amounts ofshift in the printing position for the number of printed adjustmentcharts 601, based on the amounts of shift in the printing positioncalculated in step S1112. The CPU 114 then determines the average valuescalculated in step S1115 to be the amounts of shift in the printingposition with respect to the sheet selected in step S901 of FIG. 9.After the processing of step S1115, the series of processing related toFIG. 11 ends. Then, the processing proceeds to step S912 of FIG. 9.

In step S1116, the CPU 114 displays an error screen 1400 illustrated inFIG. 14 on the displaying unit of the operation unit 120. The errorscreen 1400 is a screen for notifying the user that the analysis of theimage data on the adjustment chart 601 failed and the printing positionhas not been adjusted. After the processing of step S1116, the series ofprocessing related to FIG. 11 ends and the series of processing relatedto FIG. 9 ends.

That is the details of the series of processing (step S1100 in FIG. 11)for performing automatic adjustment of the printing position by scanningthe adjustment chart 601 by pressing plate reading.

Next, a series of processing for performing automatic adjustment of theprinting position by scanning the adjustment chart 601 by ADF readingwill be described with reference to the flowchart illustrated in FIG.15. The processing is performed by the CPU 114 of the controller unit110 executing a control program that is read from the ROM 112 or the HDD115 and loaded into the RAM 113.

In step S1501, the CPU 114 displays the designation screen 1200illustrated in FIG. 12 on the displaying unit of the operation unit 120.Then, the processing proceeds to step S1502.

In step S1502, the CPU 114 receives designation of the number ofadjustment charts 601 to print from the user on the designation screen1200. Then, the processing proceeds to step S1503.

In step S1503, the CPU 114 instructs the image forming unit 151 to printadjustment charts 601 as many as designated in step S1502. At that time,the image data on the adjustment chart 601 is read from the RAM 113 orthe HDD 115 and transferred to the printer engine 150. Receiving theprint instruction, the image forming unit 151 prints the adjustmentchart 601 on the sheets fed from the feeding unit 140 (i.e., the sheetselected in step S901). The sheets on which the adjustment chart 601 isprinted are discharged from the printing apparatus 100. After theprocessing of step S1503, the processing proceeds to step S1504.

In step S1504, the CPU 114 displays a confirmation screen 1600 (referredto as a third reception screen) illustrated in FIG. 16 on the displayingunit of the operation unit 120. The confirmation screen 1600 is a screenfor prompting the user to set the adjustment charts 601 on the documentstacking unit 304 (document tray) of the ADF to read the images on thefront and back surfaces of the adjustment charts 601. If the userpresses a button 1601 (start reading button) on the confirmation screen1600, the processing proceeds to step S1505.

In step S1505, the CPU 114 instructs the scanner unit 130 to scan thefront and back surfaces of the adjustment chart 601 printed in stepS1503 by ADF reading. Then, the processing proceeds to step S1506.

In step S1506, the CPU 114 performs image analysis on image datagenerated by scanning the front and back surfaces of the adjustmentchart 601. The CPU 114 performs the image analysis on the image data bythe method described above with reference to FIGS. 8A and 8B. Based onthe image analysis, the CPU 114 detects the image edges of theadjustment chart 601 (front and back surfaces) and the image edges ofthe marks 620, focusing on a difference in density. The processingproceeds to step S1507.

In step S1507, the CPU 114 determines whether the image edges of theadjustment chart 601 (front and back surfaces) and the image edges ofthe marks 620 are successfully detected as a result of the detectionprocessing of step S1506. If the image edges are determined to besuccessfully detected (YES in step S1507), the processing proceeds tostep S1508. On the other hand, if it is determined that the detectionhas failed (NO in step S1507), the processing proceeds to step S1513.Examples of the case where the CPU 114 determines it to be “NO” in stepS1507 include where a difference in density between the background ofthe sheet on which the adjustment chart 601 is printed and the marks 620is so small that the image edges of the marks 620 fail to be properlydetected.

In step S1508, the CPU 114 calculates the lengths of the portions (a) to(j) illustrated in FIG. 6 from the image edges of the adjustment chart601 (front surface) and the image edges of the marks 620 detected instep S1506. Then, the processing proceeds to step S1509.

In step S1509, the CPU 114 calculates the lengths of the portions (k) to(r) illustrated in FIG. 6 from the image edges of the adjustment chart601 (back surface) and the image edges of the marks 620 detected in stepS1506. Then, the processing proceeds to step S1510.

In step S1510, the CPU 114 calculates the amounts of shift in theprinting position 712 based on the lengths of the portions (a) to (j)calculated in step S1508 and the lengths of the portions (k) to (r)calculated in step S1509. Then, the processing proceeds to step S1511.The amounts of shift in the printing position 712 are calculated byusing the formulas described above with reference to FIG. 7.

In step S1511, the CPU 114 determines whether the amounts of shift inthe printing position have been calculated for the number of printedadjustment charts 601 (i.e., the number of adjustment charts 601designated in step S1502). The CPU 114 performs the determinationprocessing of step S1511 by storing the number of times of processing ofstep S1511 into the HDD 115 or the RAM 113 as a counter, and comparingthe value of the stored counter with the number of adjustment charts 601designated in step S1502. As a result of the determination in stepS1511, if the CPU 114 determines it to be “YES” (YES in step S1511), theprocessing proceeds to step S1512. On the other hand, if the CPU 114determines it to be “NO” (NO in step S1511), the processing returns tostep S1505 and the CPU 114 continues the subsequent processing.

In step S1512, the CPU 114 calculates the average values of the amountsof shift in the printing position for the number of printed adjustmentcharts 601 based on the amounts of shift in the printing positioncalculated in step S1510. The CPU 114 then determines the average valuescalculated in step S1512 to be the amounts of shift in the printingposition with respect to the sheet selected in step S901 of FIG. 9.After the processing of step S1512, the series of processing related toFIG. 15 ends. Then, the processing proceeds to step S912 of FIG. 9.

In step S1513, the CPU 114 displays the error screen 1400 illustrated inFIG. 14 on the displaying unit of the operation unit 120. After theprocessing of step S1513, the series of processing related to FIG. 15ends and the series of processing related to FIG. 9 ends.

That is the details of the series of processing (step S1500 in FIG. 15)for performing automatic adjustment of the printing position by scanningthe adjustment chart 601 by ADF reading.

As described above, in the first exemplary embodiment, the CPU 114instructs the image forming unit 151 to print the adjustment chart 601on a sheet for adjusting a shift in the printing position. Then, the CPU114 determines whether the printed adjustment chart 601 can be scannedby ADF reading, based on the physical properties of the sheet. If theCPU 114 determines that the printed adjustment chart 601 can be scannedby ADF reading, the CPU 114 controls a screen display so that the usercan arbitrarily select either of “scanning by ADF reading” and “scanningby pressing plate reading” to perform automatic adjustment of theprinting position. On the other hand, if the CPU 114 determines that theprinted adjustment chart 601 cannot be scanned by ADF reading, the CPU114 controls a screen display so that the user can arbitrarily select“scanning by pressing plate reading” to perform automatic adjustment ofthe printing position, but not “scanning by ADF reading”. In this way,according to the first exemplary embodiment, a method for adjusting theprinting position can be appropriately presented to the user based onthe physical properties of the sheet on which the adjustment chart 601is printed. In particular, if a plurality of adjustment charts 601 is tobe scanned to improve the accuracy of the amounts of shift in theprinting position, the user can easily check whether the adjustmentcharts 601 can be scanned by ADF reading. This improves the user'sconvenience.

In the first exemplary embodiment, the case is described in which theCPU 114 controls, if it is determined that the printed adjustment chart601 cannot be scanned by ADF reading, a screen display as illustrated inFIG. 10B so that the user cannot select “scanning by ADF reading”.However, it is not limited thereto. In another embodiment, the CPU 114displays a selection screen 1700 illustrated in FIG. 17 on thedisplaying unit of the operation unit 120 instead of the selectionscreen 1020 illustrated in FIG. 10B. More specifically, even if it isdetermined that the printed adjustment chart 601 cannot be scanned byADF reading, the CPU 114 may allow the user to select “scanning by ADFreading” after notifying the user of a warning 1701 that ADF reading isnot supported.

The present invention is not limited to the above-described exemplaryembodiments. Various modifications (including organic combinations ofthe exemplary embodiments) may be made based on the gist of the presentinvention, and such modifications are not intended to be excluded fromthe scope of the present invention.

For example, in the above-described exemplary embodiments, the CPU 114of the controller unit 110 of the printing apparatus 100 serves as themain constituent for the above-described various controls. However, itis not limited thereto. A print controlling unit such as an externalcontroller in a housing separate from the printing apparatus 100 may beconfigured to be able to perform part or all of the above-describedvarious controls.

The exemplary embodiments to which the present invention is applied aredescribed by using the printing apparatus 100 including the imageforming unit 151 that uses monochrome toner. However, it is not limitedthereto. The exemplary embodiments to which the present invention isapplied can be a color printing apparatus 100 including an image formingunit 151 that uses toners of a plurality of colors. For example, if afull-color printing apparatus 100 uses four colors of cyan (C), magenta(M), yellow (Y), and black (K), the printing apparatus 100 may adjust aprinting position by using black toner. The printing positions of theother colors may be adjusted with reference to the printing position ofblack.

While various examples and exemplary embodiments of the presentinvention have been described above, the gist and scope of the presentinvention are not limited to the specific descriptions in thisspecification document.

Other Embodiments

Embodiments of the present invention can also be realized by a computerof a system or apparatus that reads out and executes computer executableinstructions recorded on a storage medium (e.g., non-transitorycomputer-readable storage medium) to perform the functions of one ormore of the above-described embodiment(s) of the present invention, andby a method performed by the computer of the system or apparatus by, forexample, reading out and executing the computer executable instructionsfrom the storage medium to perform the functions of one or more of theabove-described embodiment(s). The computer may comprise one or more ofa central processing unit (CPU), micro processing unit (MPU), or othercircuitry, and may include a network of separate computers or separatecomputer processors. The computer executable instructions may beprovided to the computer, for example, from a network or the storagemedium. The storage medium may include, for example, one or more of ahard disk, a random-access memory (RAM), a read only memory (ROM), astorage of distributed computing systems, an optical disk (such as acompact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™),a flash memory device, a memory card, and the like.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

What is claimed is:
 1. A printing apparatus comprising: a printing unitconfigured to print an adjustment image for adjusting a printingposition on a sheet; a conveying unit configured to convey the sheet; areading unit configured to read an image to generate image data, thereading unit being executable to perform reading using a first readingmethod for reading an image of a sheet without conveying the sheet and asecond reading method for reading the image of the sheet while conveyingthe sheet; and a determining unit configured to determine, based on thata type of the sheet on which the adjustment image is printed is aspecific type, to read the adjustment image using the first readingmethod.
 2. The printing apparatus according to claim 1, furthercomprising: an obtaining unit configured to obtain, in a case where thereading unit reads the adjustment image using the first reading method,an amount of shift in the printing position based on image datagenerated by reading, using the first reading method, the adjustmentimage printed on the sheet, and obtain, in a case where the reading unitreads the adjustment image using the second reading method, the amountof shift in the printing position based on image data generated byreading, using the second reading method, the adjustment image printedon the sheet; and a print controlling unit configured to control theprinting unit based on the amount of shift in the printing position sothat an image is printed on the sheet.
 3. The printing apparatusaccording to claim 2, wherein the obtaining unit obtains, in a casewhere the determining unit determines to read the adjustment image usingthe first reading method, the amount of shift in the printing positionbased on the image data generated by reading, using the first readingmethod, the adjustment image printed on the sheet.
 4. The printingapparatus according to claim 2, further comprising a receiving unitconfigured to receive a first instruction for causing the reading unitto read the adjustment image using the first reading method or a secondinstruction for causing the reading unit to read the adjustment imageusing the second reading method, wherein the obtaining unit obtains, ina case where the receiving unit receives the first instruction, theamount of shift in the printing position based on the image datagenerated by reading, using the first reading method, the adjustmentimage printed on the sheet, and obtains, in a case where the receivingunit receives the second instruction, the amount of shift in theprinting position based on the image data generated by reading, usingthe second reading method, the adjustment image printed on the sheet. 5.The printing apparatus according to claim 4, further comprising adisplaying unit configured to display on a screen a first button viawhich the receiving unit receives the first instruction from a user, anda second button via which the receiving unit receives the secondinstruction from the user, wherein the obtaining unit obtains, in a casewhere the first instruction is received from the user via the firstbutton, the amount of shift in the printing position based on the imagedata generated by reading, using the first reading method, theadjustment image printed on the sheet, and obtains, in a case where thesecond instruction is received from the user via the second button, theamount of shift in the printing position based on the image datagenerated by reading, using the second reading method, the adjustmentimage printed on the sheet.
 6. The printing apparatus according to claim5, wherein the receiving unit, in a case where the determining unitdetermines to read the adjustment image using the first reading method,does not receive the second instruction even if the user presses thesecond button.
 7. The printing apparatus according to claim 5, whereinthe displaying unit displays, in a case where the determining unitdetermines to read the adjustment image using the first reading method,the first button without displaying the second button on the screen. 8.The printing apparatus according to claim 1, further comprising anotification unit configured to notify, based on that the determiningunit determines to read the adjustment image using the first readingmethod, the user that an image of the specific type of sheet cannot beread using the second reading method.
 9. The printing apparatusaccording to claim 2, further comprising a setting unit configured toset, in association with the sheet, the amount of shift in the printingposition, wherein the print controlling unit controls the printing unitbased on the amount of shift in the printing position so that the imageis printed on the sheet.
 10. The printing apparatus according to claim4, wherein the receiving unit receives a third instruction for allowinga user to input and obtain the amount of shift in the printing position,and wherein the obtaining unit obtains, in a case where the receivingunit receives the third instruction, the amount of shift in the printingposition input by the user.
 11. The printing apparatus according toclaim 1, further comprising a selecting unit configured to select, basedon a user instruction, the sheet, wherein the printing unit prints theadjustment image on the selected sheet.
 12. The printing apparatusaccording to claim 1, wherein the specific type of sheet is cardboard,tab paper, an OHP sheet, or a transparent film.
 13. A printing apparatuscomprising: a selecting unit configured to select, based on a userinstruction, a first sheet and a second sheet from a plurality ofsheets; a printing unit configured to print an adjustment image foradjusting a printing position on the first sheet or the second sheetselected by the selecting unit; a reading unit configured to read animage to generate image data; an obtaining unit configured to obtain anamount of shift in the printing position for the first sheet based onimage data generated by the reading unit reading the adjustment imageprinted on the first sheet selected by the selecting unit, and obtain anamount of shift in the printing position for the second sheet based onimage data generated by the reading unit reading the adjustment imageprinted on the second sheet selected by the selecting unit; a settingunit configured to set, in association with the first sheet, the amountof shift in the printing position for the first sheet obtained by theobtaining unit, and set, in association with the second sheet, theamount of shift in the printing position for the second sheet obtainedby the obtaining unit; and a print controlling unit configured tocontrol the printing unit based on the amount of shift in the printingposition for the first sheet set by the setting unit so that an image isprinted on the first sheet, and control the printing unit based on theamount of shift in the printing position for the second sheet set by thesetting unit so that the image is printed on the second sheet.
 14. Theprinting apparatus according to claim 13, further comprising adesignating unit configured to designate the first sheet or the secondsheet as a sheet on which the image is printed by the printing unit,wherein the print controlling unit controls, in a case where the firstsheet is designated by the designating unit, the printing unit based onthe amount of shift in the printing position for the first sheet set bythe setting unit so that the image is printed on the first sheet, andcontrols, in a case where the second sheet is designated by thedesignating unit, the printing unit based on the amount of shift in theprinting position for the second sheet set by the setting unit so thatthe image is printed on the second sheet.
 15. A printing apparatuscomprising: a printing unit configured to print an adjustment image foradjusting a printing position on a sheet; a conveying unit configured toconvey the sheet on which the adjustment image is printed; a readingunit configured to read an image to generate image data, the readingunit being executable to perform reading using a first reading methodfor reading an image of a sheet without conveying the sheet or a secondreading method for reading the image of the sheet while conveying thesheet; a receiving unit configured to receive a first instruction forcausing the reading unit to read the adjustment image using the firstreading method or a second instruction for causing the reading unit toread the adjustment image using the second reading method; a displayingunit configured to display on a screen a first button via which thereceiving unit receives the first instruction from a user and a secondbutton via which the receiving unit receives the second instruction fromthe user; an obtaining unit configured to obtain, in a case where thefirst instruction is received from the user via the first button, anamount of shift in the printing position based on image data generatedby reading, using the first reading method, the adjustment image printedon the sheet, and obtain, in a case where the second instruction isreceived from the user via the second button, the amount of shift in theprinting position based on image data generated by reading, using thesecond reading method, the adjustment image printed on the sheet; and aprint controlling unit configured to control the printing unit based onthe amount of shift in the printing position so that an image is printedon the sheet, wherein the displaying unit displays, in a case where atype of the sheet on which the adjustment image is to be printed is aspecific type, the first button without displaying the second button onthe screen.
 16. A control method in a printing apparatus, the controlmethod comprising: printing, by a printing unit, an adjustment image foradjusting a printing position on a sheet; conveying, by a conveyingunit, the sheet on which the adjustment image is printed; reading, by areading unit, an image to generate image data, the reading unit beingexecutable to perform reading by a first reading method for reading animage of a sheet without conveying the sheet or a second reading methodfor reading the image of the sheet while conveying the sheet; anddetermining, based on that a type of the sheet on which the adjustmentimage is to be printed is a specific type, to read the adjustment imageby the first reading unit.
 17. The control method according to claim 16,further comprising: obtaining, in a case where the reading reads theadjustment image using the first reading method, an amount of shift inthe printing position based on image data generated by reading, usingthe first reading method, the adjustment image printed on the sheet, andobtaining, in a case where the reading reads the adjustment image usingthe second reading method, the amount of shift in the printing positionbased on image data generated by reading, using the second readingmethod, the adjustment image printed on the sheet; and controlling theprinting based on the amount of shift in the printing position so thatan image is printed on the sheet.
 18. A non-transitory computer readablestorage medium for storing a computer program for controlling a printingapparatus, the computer program comprising: a code to print anadjustment image for adjusting a printing position on a sheet; a code toconvey the sheet on which the adjustment image is printed; a code toread an image to generate image data, the code to read being executableto perform reading by a first reading method for reading an image of asheet without conveying the sheet or a second reading method for readingthe image of the sheet while conveying the sheet; and a code todetermine, based on that a type of the sheet on which the adjustmentimage is to be printed is a specific type, to read the adjustment imageby the first reading method.
 19. The non-transitory computer readablestorage medium according to claim 18, further comprising: a code toobtain, in a case where the reading reads the adjustment image using thefirst reading method, an amount of shift in the printing position basedon image data generated by reading, using the first reading method, theadjustment image printed on the sheet, and a code to obtain, in a casewhere the reading reads the adjustment image using the second readingmethod, the amount of shift in the printing position based on image datagenerated by reading, using the second reading method, the adjustmentimage printed on the sheet; and a code to control the printing based onthe amount of shift in the printing position so that an image is printedon the sheet.